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NTPQ(8) FreeBSD System Manager's Manual NTPQ(8)
NAMEntpq -- standard NTP query program
SYNOPSISntpq [-inp] [-ccommand] [host] [...]
DESCRIPTION
The ntpq utility is used to monitor NTP daemon ntpd(8) operations and
determine performance. It uses the standard NTP mode 6 control message
formats defined in Appendix B of the NTPv3 specification RFC1305. The
same formats are used in NTPv4, although some of the variables have
changed and new ones added. The description on this page is for the
NTPv4 variables.
The program can be run either in interactive mode or controlled using
command line arguments. Requests to read and write arbitrary variables
can be assembled, with raw and pretty-printed output options being avail-
able. The ntpq can also obtain and print a list of peers in a common
format by sendingmultiple queries to the server.
If one or more request options is included on the command line when ntpq
is executed, each of the requests will be sent to the NTP servers running
on each of the hosts given as command line arguments, or on localhost by
default. If no request options are given, ntpq will attempt to read com-
mands from the standard input and execute these on the NTP server running
on the first host given on the command line, again defaulting to local-
host when no other host is specified. The ntpq utility will prompt for
commands if the standard input is a terminal device.
The ntpq utility uses NTP mode 6 packets to communicate with the NTP
server, and hence can be used to query any compatible server on the net-
work which permits it. Note that since NTP is a UDP protocol this commu-
nication will be somewhat unreliable, especially over large distances in
terms of network topology. The ntpq utility makes one attempt to
retransmit requests, and will time requests out if the remote host is not
heard from within a suitable timeout time.
For examples and usage, see the "NTP Debugging Techniques" page (avail-
able as part of the HTML documentation provided in /usr/share/doc/ntp).
The following options are available:
-4 Force DNS resolution of following host names on the command line
to the IPv4 namespace.
-6 Force DNS resolution of following host names on the command line
to the IPv6 namespace.
-c The following argument is interpreted as an interactive format
command and is added to the list of commands to be executed on
the specified host(s). Multiple -c options may be given.
-d Turn on debugging mode.
-i Force ntpq to operate in interactive mode. Prompts will be writ-
ten to the standard output and commands read from the standard
input.
-n Output all host addresses in dotted-quad numeric format rather
than converting to the canonical host names.
-p Print a list of the peers known to the server as well as a sum-
mary of their state. This is equivalent to the peers interactive
command.
Note that in contexts where a host name is expected, a -4 qualifier pre-
ceding the host name forces DNS resolution to the IPv4 namespace, while a
-6 qualifier forces DNS resolution to the IPv6 namespace. Specifying a
command line option other than -i or -n will cause the specified query
(queries) to be sent to the indicated host(s) immediately. Otherwise,
ntpq will attempt to read interactive format commands from the standard
input.
InternalCommands
Interactive format commands consist of a keyword followed by zero to four
arguments. Only enough characters of the full keyword to uniquely iden-
tify the command need be typed. The output of a command is normally sent
to the standard output, but optionally the output of individual commands
may be sent to a file by appending a `>', followed by a file name, to the
command line. A number of interactive format commands are executed
entirely within the ntpq utility itself and do not result in NTP mode 6
requests being sent to a server. These are described following.
? [command_keyword]
help [command_keyword]
A `?' by itself will print a list of all the command keywords
known to this incarnation of ntpq. A `?' followed by a command
keyword will print function and usage information about the com-
mand. This command is probably a better source of information
about ntpq than this manual page.
addvarsvariable_name[=value...]
rmvarsvariable_name...clearvars
The data carried by NTP mode 6 messages consists of a list of
items of the form `variable_name=value', where the `=value' is
ignored, and can be omitted, in requests to the server to read
variables. The ntpq utility maintains an internal list in which
data to be included in control messages can be assembled, and
sent using the readlist and writelist commands described below.
The addvars command allows variables and their optional values to
be added to the list. If more than one variable is to be added,
the list should be comma-separated and not contain white space.
The rmvars command can be used to remove individual variables
from the list, while the clearlist command removes all variables
from the list.
cooked Causes output from query commands to be "cooked", so that vari-
ables which are recognized by ntpq will have their values refor-
matted for human consumption. Variables which ntpq thinks should
have a decodable value but did not are marked with a trailing
`?'.
debugmore | less | off
Turns internal query program debugging on and off.
delaymilliseconds
Specify a time interval to be added to timestamps included in
requests which require authentication. This is used to enable
(unreliable) server reconfiguration over long delay network paths
or between machines whose clocks are unsynchronized. Actually
the server does not now require timestamps in authenticated
requests, so this command may be obsolete.
hosthostname
Set the host to which future queries will be sent. Hostname may
be either a host name or a numeric address.
hostnamesyes | no
If yes is specified, host names are printed in information dis-
plays. If no is specified, numeric addresses are printed
instead. The default is yes, unless modified using the command
line -n switch.
keyidkeyid
This command specifies the key number to be used to authenticate
configuration requests. This must correspond to a key number the
server has been configured to use for this purpose.
ntpversion1 | 2 | 3 | 4
Sets the NTP version number which ntpq claims in packets.
Defaults to 3, Note that mode 6 control messages (and modes, for
that matter) did not exist in NTP version 1. There appear to be
no servers left which demand version 1.
passwd This command prompts for a password (which will not be echoed)
which will be used to authenticate configuration requests. The
password must correspond to the key configured for NTP server for
this purpose.
quit Exit ntpq.
raw Causes all output from query commands is printed as received from
the remote server. The only formatting/interpretation done on
the data is to transform nonascii data into a printable (but
barely understandable) form.
timeoutmilliseconds
Specify a timeout period for responses to server queries. The
default is about 5000 milliseconds. Note that since ntpq retries
each query once after a timeout, the total waiting time for a
timeout will be twice the timeout value set.
ControlMessageCommands
Each association known to an NTP server has a 16 bit integer association
identifier. NTP control messages which carry peer variables must iden-
tify the peer the values correspond to by including its association ID.
An association ID of 0 is special, and indicates the variables are system
variables, whose names are drawn from a separate name space.
Control message commands result in one or more NTP mode 6 messages being
sent to the server, and cause the data returned to be printed in some
format. Most commands currently implemented send a single message and
expect a single response. The current exceptions are the peers command,
which will send a preprogrammed series of messages to obtain the data it
needs, and the mreadlist and mreadvar commands, which will iterate over a
range of associations.
associations
Obtains and prints a list of association identifiers and peer
statuses for in-spec peers of the server being queried. The list
is printed in columns. The first of these is an index numbering
the associations from 1 for internal use, the second the actual
association identifier returned by the server and the third the
status word for the peer. This is followed by a number of col-
umns containing data decoded from the status word. See the peers
command for a decode of the `condition' field. Note that the
data returned by the associations command is cached internally in
ntpq. The index is then of use when dealing with stupid servers
which use association identifiers which are hard for humans to
type, in that for any subsequent commands which require an asso-
ciation identifier as an argument, the form and index may be used
as an alternative.
clockvar [assocID] [variable_name[=value...]] ...cv [assocID] [variable_name[=value...]] ...
Requests that a list of the server's clock variables be sent.
Servers which have a radio clock or other external synchroniza-
tion will respond positively to this. If the association identi-
fier is omitted or zero the request is for the variables of the
`system clock' and will generally get a positive response from
all servers with a clock. If the server treats clocks as pseudo-
peers, and hence can possibly have more than one clock connected
at once, referencing the appropriate peer association ID will
show the variables of a particular clock. Omitting the variable
list will cause the server to return a default variable display.
lassociations
Obtains and prints a list of association identifiers and peer
statuses for all associations for which the server is maintaining
state. This command differs from the associations command only
for servers which retain state for out-of-spec client associa-
tions (i.e., fuzzballs). Such associations are normally omitted
from the display when the associations command is used, but are
included in the output of lassociations.
lpassociations
Print data for all associations, including out-of-spec client
associations, from the internally cached list of associations.
This command differs from passociations only when dealing with
fuzzballs.
lpeers Like R peers, except a summary of all associations for which the
server is maintaining state is printed. This can produce a much
longer list of peers from fuzzball servers.
mreadlistassocIDassocIDmrlassocIDassocID
Like the readlist command, except the query is done for each of a
range of (nonzero) association IDs. This range is determined
from the association list cached by the most recent associations
command.
mreadvarassocIDassocID [variable_name[=value...]]
mrvassocIDassocID [variable_name[=value...]]
Like the readvar command, except the query is done for each of a
range of (nonzero) association IDs. This range is determined
from the association list cached by the most recent associations
command.
opeers An old form of the peers command with the reference ID replaced
by the local interface address.
passociations
Displays association data concerning in-spec peers from the
internally cached list of associations. This command performs
identically to the associations except that it displays the
internally stored data rather than making a new query.
peers Obtains a current list peers of the server, along with a summary
of each peer's state. Summary information includes the address
of the remote peer, the reference ID (0.0.0.0 if this is
unknown), the stratum of the remote peer, the type of the peer
(local, unicast, multicast or broadcast), when the last packet
was received, the polling interval, in seconds, the reachability
register, in octal, and the current estimated delay, offset and
dispersion of the peer, all in milliseconds. The character at
the left margin of each line shows the synchronization status of
the association and is a valuable diagnostic tool. The encoding
and meaning of this character, called the tally code, is given
later in this page.
pstatusassocID
Sends a read status request to the server for the given associa-
tion. The names and values of the peer variables returned will
be printed. Note that the status word from the header is dis-
played preceding the variables, both in hexadecimal and in pid-
geon English.
readlistassocIDrlassocID
Requests that the values of the variables in the internal vari-
able list be returned by the server. If the association ID is
omitted or is 0 the variables are assumed to be system variables.
Otherwise they are treated as peer variables. If the internal
variable list is empty a request is sent without data, which
should induce the remote server to return a default display.
readvarassocIDvariable_name[=value] ...rvassocIDvariable_name[=value] ...
Requests that the values of the specified variables be returned
by the server by sending a read variables request. If the asso-
ciation ID is omitted or is given as zero the variables are sys-
tem variables, otherwise they are peer variables and the values
returned will be those of the corresponding peer. Omitting the
variable list will send a request with no data which should
induce the server to return a default display. The encoding and
meaning of the variables derived from NTPv3 is given in RFC-1305;
the encoding and meaning of the additional NTPv4 variables are
given later in this page.
writevarassocIDvariable_name[=value] ...
Like the readvar request, except the specified variables are
written instead of read.
writelist [assocID]
Like the readlist request, except the internal list variables are
written instead of read.
TallyCodes
The character in the left margin in the `peers' billboard, called the
tally code, shows the fate of each association in the clock selection
process. Following is a list of these characters, the pigeon used in the
rv command, and a short explanation of the condition revealed.
space (reject) The peer is discarded as unreachable, synchronized to
this server (synch loop) or outrageous synchronization distance.
x (falsetick) The peer is discarded by the intersection algorithm
as a falseticker.
. (excess) The peer is discarded as not among the first ten peers
sorted by synchronization distance and so is probably a poor can-
didate for further consideration.
- (outlyer) The peer is discarded by the clustering algorithm as an
outlyer.
+ (candidat) The peer is a survivor and a candidate for the combin-
ing algorithm.
# (selected) The peer is a survivor, but not among the first six
peers sorted by synchronization distance. If the association is
ephemeral, it may be demobilized to conserve resources.
* (sys.peer) The peer has been declared the system peer and lends
its variables to the system variables.
o (pps.peer) The peer has been declared the system peer and lends
its variables to the system variables. However, the actual sys-
tem synchronization is derived from a pulse-per-second (PPS) sig-
nal, either indirectly via the PPS reference clock driver or
directly via kernel interface.
SystemVariables
The status, leap, stratum, precision, rootdelay, rootdispersion, refid,
reftime, poll, offset, and frequency variables are described in RFC-1305
specification. Additional NTPv4 system variables include the following.
version
Everything you might need to know about the software version and
generation time.
processor
The processor and kernel identification string.
system The operating system version and release identifier.
state The state of the clock discipline state machine. The values are
described in the architecture briefing on the NTP Project page
linked from www.ntp.org.
peer The internal integer used to identify the association currently
designated the system peer.
jitter The estimated time error of the system clock measured as an expo-
nential average of RMS time differences.
stability
The estimated frequency stability of the system clock measured as
an exponential average of RMS frequency differences.
When the NTPv4 daemon is compiled with the OpenSSL software library,
additional system variables are displayed, including some or all of the
following, depending on the particular dance:
flags The current flags word bits and message digest algorithm identi-
fier (NID) in hex format. The high order 16 bits of the four-
byte word contain the NID from the OpenSSL ligrary, while the
low-order bits are interpreted as follows:
0x01 autokey enabled
0x02 NIST leapseconds file loaded
0x10 PC identity scheme
0x20 IFF identity scheme
0x40 GQ identity scheme
hostname
The name of the host as returned by the Unix gethostname()
library function.
hostkey
The NTP filestamp of the host key file.
cert A list of certificates held by the host. Each entry includes the
subject, issuer, flags and NTP filestamp in order. The bits are
interpreted as follows:
0x01 certificate has been signed by the server
0x02 certificate is trusted
0x04 certificate is private
0x08 certificate contains errors and should not be trusted
leapseconds
The NTP filestamp of the NIST leapseconds file.
refresh
The NTP timestamp when the host public cryptographic values were
refreshed and signed.
signature
The host digest/signature scheme name from the OpenSSL library.
tai The TAI-UTC offset in seconds obtained from the NIST leapseconds
table.
PeerVariables
The status, srcadr, srcport, dstadr, dstport, leap, stratum, precision,
rootdelay, rootdispersion, readh, hmode, pmode, hpoll, ppoll, offset,
delay, dspersion, reftime variables are described in the RFC-1305 speci-
fication, as are the timestamps org, rec and xmt. Additional NTPv4 sys-
tem variables include the following.
flash The flash code for the most recent packet received. The encoding
and meaning of these codes is given later in this page.
jitter The estimated time error of the peer clock measured as an expo-
nential average of RMS time differences.
unreach
The value of the counter which records the number of poll inter-
vals since the last valid packet was received.
When the NTPv4 daemon is compiled with the OpenSSL software library,
additional peer variables are displayed, including the following:
flags The current flag bits. This word is the server host status word
with additional bits used by the Autokey state machine. See the
source code for the bit encoding.
hostname
The server host name.
initkey key
The initial key used by the key list generator in the Autokey
protocol.
initsequence index
The initial index used by the key list generator in the Autokey
protocol.
signature
The server message digest/signature scheme name from the OpenSSL
software library.
timestamp time
The NTP timestamp when the last Autokey key list was generated
and signed.
FlashCodes
The flash code is a valuable debugging aid displayed in the peer vari-
ables list. It shows the results of the original sanity checks defined
in the NTP specification RFC-1305 and additional ones added in NTPv4.
There are 12 tests designated TEST1 through TEST12. The tests are per-
formed in a certain order designed to gain maximum diagnostic information
while protecting against accidental or malicious errors. The flash vari-
able is initialized to zero as each packet is received. If after each
set of tests one or more bits are set, the packet is discarded.
Tests TEST1 through TEST3 check the packet timestamps from which the off-
set and delay are calculated. If any bits are set, the packet is dis-
carded; otherwise, the packet header variables are saved. TEST4 and
TEST5 are associated with access control and cryptographic authentica-
tion. If any bits are set, the packet is discarded immediately with
nothing changed.
Tests TEST6 through TEST8 check the health of the server. If any bits
are set, the packet is discarded; otherwise, the offset and delay rela-
tive to the server are calculated and saved. TEST9 checks the health of
the association itself. If any bits are set, the packet is discarded;
otherwise, the saved variables are passed to the clock filter and mitiga-
tion algorithms.
Tests TEST10 through TEST12 check the authentication state using Autokey
public-key cryptography, as described in the AuthenticationOptions sec-
tion of ntp.conf(5). If any bits are set and the association has previ-
ously been marked reachable, the packet is discarded; otherwise, the
originate and receive timestamps are saved, as required by the NTP proto-
col, and processing continues.
The flash bits for each test are defined as follows.
0x001 (TEST1) Duplicate packet. The packet is at best a casual
retransmission and at worst a malicious replay.
0x002 (TEST2) Bogus packet. The packet is not a reply to a message
previously sent. This can happen when the NTP daemon is
restarted and before somebody else notices.
0x004 (TEST3) Unsynchronized. One or more timestamp fields are
invalid. This normally happens when the first packet from a peer
is received.
0x008 (TEST4) Access is denied. See the AccessControlSupport section
of ntp.conf(5).
0x010 (TEST5) Cryptographic authentication fails. See the
AuthenticationOptions section of ntp.conf(5).
0x020 (TEST6) The server is unsynchronized. Wind up its clock first.
0x040 (TEST7) The server stratum is at the maximum than 15. It is
probably unsynchronized and its clock needs to be wound up.
0x080 (TEST8) Either the root delay or dispersion is greater than one
second, which is highly unlikely unless the peer is unsynchro-
nized to Mars.
0x100 (TEST9) Either the peer delay or dispersion is greater than one
second, which is higly unlikely unless the peer is on Mars.
0x200 (TEST10) The autokey protocol has detected an authentication
failure. See the AuthenticationOptions section of ntp.conf(5).
0x400 (TEST11) The autokey protocol has not verified the server or peer
is proventic and has valid public key credentials. See the
AuthenticationOptions section of ntp.conf(5).
0x800 (TEST12) A protocol or configuration error has occurred in the
public key algorithms or a possible intrusion event has been
detected. See the AuthenticationOptions section of ntp.conf(5).
SEE ALSOntp.conf(5), ntpd(8), ntpdc(8)BUGS
The peers command is non-atomic and may occasionally result in spurious
error messages about invalid associations occurring and terminating the
command. The timeout time is a fixed constant, which means you wait a
long time for timeouts since it assumes sort of a worst case. The pro-
gram should improve the timeout estimate as it sends queries to a partic-
ular host, but does not.
FreeBSD 10.1 May 17, 2006 FreeBSD 10.1